kstd/libc: implement basic memmove

1 files changed, 21 insertions, 0 deletions

diff --git a/libs/kstd/src/libc/string.cpp b/libs/kstd/src/libc/string.cpp
index 319f6fd..b7d4c6b 100644
--- a/libs/kstd/src/libc/string.cpp
+++ b/libs/kstd/src/libc/string.cpp
@@ -27,6 +27,27 @@ namespace kstd::libc
 
       return std::bit_cast<char>(*mismatched.in1) - std::bit_cast<char>(*mismatched.in2);
     }
+
+    auto memmove(void * dest, void const * src, std::size_t size) -> void *
+    {
+      auto dest_span = std::span{static_cast<std::byte *>(dest), size};
+      auto src_span = std::span{static_cast<std::byte const *>(src), size};
+      if (dest < src)
+      {
+        for (std::size_t i = 0; i < size; ++i)
+        {
+          dest_span[i] = src_span[i];
+        }
+      }
+      else
+      {
+        for (std::size_t i = size; i > 0; --i)
+        {
+          dest_span[i - 1] = src_span[i - 1];
+        }
+      }
+      return dest;
+    }
   }
 
 }  // namespace kstd::libc
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